You can directly upgrade from vRealize Operations for Horizon 6.2/6.2.1 to vRealize Operations for Horizon 6.3. If you have vRealize Operations for Horizon 1.6 or 1.7 installed in your environment, you must first migrate to vRealize Operations for Horizon 6.1 and then upgrade to vRealize Operations for Horizon 6.3.

There is a dependency on vCenter adapter because the vCenter adapter instances are also bundles with the Horizon solution. You cannot just select the Horizon adapter and click the Remove Instance button to remove the Horizon adapter instance. Doing so leads to the deletion of both Horizon and vCenter adapter instances.